1. Field of the Invention
The invention relates to a liquid-like dispersion containing solid, flame-retardant, particulate dispersants. The solids are dispersed in a liquid carrier and the dispersion contains at least 1 to about 3 weight percent* of a hyperdispersant. The dispersion is pourable at room temperature. The dispersion is useful as an additive for polymers which, when added during processing, imparts flame retardancy to the finished polymeric product. FNT *All percentages used herein will be in terms of weight percent unless otherwise indicated.
2. Description of the Prior Art
Additives such as particulate colorant pigments have been incorporated into polymers such as thermoplastic polymers by first blending the solid additive with virgin polymer pellets and feeding the blend into a processing chamber such as an extruder feed hopper, following which the additive and resin are further processed under high temperature and the blend is extruded to form a semi-finished product. Usually, in such a process, the additive and polymer do not mix together in a uniform manner. Further, fine powder additives often create dust, problems which may be damaging to both health and environment.
Also known is a process wherein particulate pigments have been added to a liquid carrier to produce color dispersions. These dispersions have then been added to the polymer during processing. Such liquid carriers and particulate polymeric additives, when mixed, are metered directly into the polymer processing apparatus. Such liquid dispersions also may have nonuniformity problems and solids concentrations rarely have contained more than 45 to 50 percent solids.
Also known is a flame retardant composition of a mixture of up to 80 percent antimony oxide powder/decabromodiphenyl oxide powder (3:1) dispersed in 20 percent liquid carrier to produce a paste-like mixture which was then mixed with a thermoplastic by pumping into a plasticating extruder to produce a flame retardant finished product.